Question

An isotone of Ge${}_{32}^{77}$ is:
i. Ge${}_{32}^{76}$ ii. As${}_{33}^{78}$
iii. Se${}_{34}^{79}$ iv. Se${}_{34}^{78}$

• A. only (i) and (ii)
• B. only (ii) and (iii)
• C. only (ii) and (iv)
• D. (ii), (iii) and (iv)

Answer 1

Answer: (B)

only (ii) and (iii)

Isotones have same number of neutrons.

i. Ge${}_{32}^{76}$ ; n = 76 - 32 = 44

ii. As${}_{33}^{78}$ : n = 78 - 33 = 45

iii. Se${}_{34}^{79}$ : n = 79 - 34 = 45

iv. Se${}_{34}^{78}$ : n = 78 - 34 = 44

Hence the correct option is B.